14-3-3c-mediated transport of plakoglobin to the cell border is required for the initiation of desmosome assembly in vitro and in vivo

The regulation of cell–cell adhesion is important for the processes of tissue formation and morphogenesis. Here, we report that loss of 14-3-3c leads to a decrease in cell–cell adhesion and a defect in the transport of plakoglobin and other desmosomal proteins to the cell border in HCT116 cells and cells of the mouse testis. 14-3-3c binds to plakoglobin in a PKCm-dependent fashion, resulting in microtubule-dependent transport of plakoglobin to cell borders. Transport of plakoglobin to the border is dependent on the KIF5B– KLC1 complex. Knockdown of KIF5B in HCT116 cells, or in the mouse testis, results in a phenotype similar to that observed upon 14-3-3c knockdown. Our results suggest that loss of 14-3-3c leads to decreased desmosome formation and a decrease in cell–cell adhesion in vitro, and in the mouse testis in vivo, leading to defects in testis organization and spermatogenesis.